b. Locate the Insertion Site. The insertion site is located in the second
intercostal space (the area between the second and third ribs, counting from the top) at
the mid-clavicular line (an imaginary line perpendicular to the ribs approximately in line
with the casualty's nipple) on the same side of the chest as the penetrating wound.
Figure 4-5 shows the location of the second intercostal space. Figure 4-6 shows the
Figure 4-5. Locating the second intercostal space (wound on casualty's left side).
Figure 4-6. Locating the mid-clavicular line (wound on casualty's left side).
c. Prepare Catheter/Needle Unit. Remove the catheter/needle unit from its
packaging and then remove the protective covering.
d. Insert the Catheter/Needle. Firmly insert the needle (with catheter covering)
into the skin above the top of the third rib into the second intercostal space at a 90-
degree angle (figure 4-6). Continue inserting the needle until the chest cavity has been
penetrated. You will feel a "pop" as the needle enters the chest cavity. A hiss of
escaping air under pressure should be heard.